#include<bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define ld double
using namespace std;

const int N = 35, INF = 0x3f3f3f3f;

int n;
ld st, ans = 0;
vector<ld> a, b;

void dfs(int i, int j, ld v, ld sum)
{
    if (i == a.size() && j == b.size()) {
        ans = max(ans, sum / n);
        return;
    }
    if (i != a.size()) {
        ld now = v + a[i];
        dfs(i + 1, j, now, sum + now);
    }
    if (j != b.size()) {
        ld now = v * b[j];
        dfs(i, j + 1, now, sum + now);
    }
}

void solve()
{
    cin >> n >> st;
    for (int i = 1;i <= n;i++) {
        char op;ld x;cin >> op >> x;
        if (op == '+') a.push_back(x);
        else b.push_back(x);
    }
    sort(a.begin(), a.end(), greater<ld>());
    sort(b.begin(), b.end(), greater<ld>());

    dfs(0, 0, st, 0);
    cout << ans;
}

signed main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
#define ONLINE_JUDGE
#ifndef ONLINE_JUDGE
    std::istringstream in(R"()");
    std::cin.rdbuf(in.rdbuf());
#endif
    int T = 1;
    //cin>>T;
    cout << fixed << setprecision(10);
    for (int i = 1;i <= T;i++) {
        solve();
    }
}